Computing-machine.



J. N. THORNTON.

COMPUTING MACHINE.

APPLICATION FILED APR.5,1912.

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J. N. THORNTON.

COMPUTING MACHINE.

APPLICATION FILED Ams, 1912.

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l. N. THURNTON.

COMPUTING MACHINE.

APPLICATION FILED Ams. 1912.

Patented May 29, 1917.

3 SHEETS-SHEET 3.

'mman' Y 'UNXTED STATES PATENT OFFICE.

JOHN N. THORNTON, OF JERSEY CITY, ANIENV JERSEY, ASSXGNOR, BY MESNE ASSIGN- MENTS, TO UNDERWOOD COMPUTING MACHINE CNLPNY, OF NEW YORK, N. Y., A

CORPORATlQN VOF NEW YORK.

COMPUTING-MACHINE.

Specification of Letters Patent.

attested aia-y ea, i917.

Application inea Api-.i1 5, 1912. serial Nd. 685,531.

To (illecito/1n t 'may concern.' v y Be it known that I, JOHN N. THORNTON, a citizen oit the United States, residing in Jersey City, in the county of Hudson and State of New Jersey, have invented certain new and useful improvements in Computing-Machines, of which the following is a specification.

rlhis invention relates to computing machines, of thel kind disclosed in United States Patent to Hans Hanson, No. 905,421, dated December 1,1908, and in the British Patent No.l 33.20 oit 1912, in which computation pins are set up by the keys, and then employed toA drive the dial wheels, and in which a set 'of tens-carrying trains is operable by the general operator oit the ina,- ehine upon its return stroke, and is an imf provement on an application of Frederick fr. Hart, No. (369,751, iled Januaryb, 1912.

The principal object of the present ini vention is to provide.inexpensive, simple', reliable and durable means for preventing faulty action of the machine, due to liability of'overthrow of the dial or computing wheels or the tenscarrying trains.

1n the type of the machine shown in the patents referred to above, the computing wheels, when they have completed one cycle of movement, set members of a tenscarrying train, which members are subse quentlygiven`amovement by the general operator for? the purpose of carryingv from lower'to higher orders throughout the com- 1iuting wheels. Itv has' been heretofore aroi ,i

posed to have therge'neral operator, vadtlie completion of' its .initial stroke, 'ca l'l into action overthrow-preventing means, yone'for each' numeral wheel, to prevent overthrow thereof, andtoA have devices individual to each denomination'or controlling the same overthrow -proventing means during the carrying operation. Such a construction is disclosed in the application of Frederick A, Hart, No. 655,680, iledctober 20, 1911.

lt has falso been proposed to prov-ide means' to prevent overthrow of the tenscarrying members which are preliminarily set Y when numeral wheel completes its c vcle of movement. Such a. construction `is disclosed in. the application of Frederick A. i, t, No. G69,751,.`1led January G, 1912.

in the construction which l have illustrated, a stop or chec r. is normally inv position to prevent overthrow of any memberof the tens-carrying train Vwhich is to be -nial position..

preliininarily set upby a dial or computing wheel, and said check i'scarried on the shaft which carries thespursffor completing the opera-tion of the tens-carrying train; and each or' the spursy is 'provided with a dwell or locking edge which prevents overthrow oi the teiisrarryin'g train when the latter has'beendriven vby a spur; These spurs operate the carry-over trains to rotate the dial wheels Veach one/point; andI in order to prevent voverthrow oi thefdial or computing wheels when opeated by the carryover trains, there is also preferably provided on said spur shaft, a series of cams, which call into action devices for looking the dial wheels against overthrow; these preferably being the same locks that are employed at the conclusion of the forward stroke of the general operator, as above explained,

The spurs are arranged helically along their shaft, so as to become effective one after another, and the aforesaid cams for locking the dial wheels have a correspond ing helical arrangement, so that the dial wheel locks are actuated one after another at the proper points. I

Other 'features and advantages will hereinafter appear.-

ln the accompanying drawings,

Figure "1 represents a diagrammatical sectional side view o a computing machine o' .the Underwood-HansonUtype, yshowing' the present invention applied thereto.

Fig. ,is a plan view o1 the 4cmmputing whecls'and some allied parts.

Fig. 3 is a side view 'of the same in nor- Figs. 11, 5 and 6 show a computing wheel and sonne assoeiatedparts in various positions of the vcarry-over mechanism.

E 7 isL a rear ,view of lthe computing wheels andv some `allied parts.y

Fig. 8 isa viewer a locking member for dial wheel.

Fig. 9 is a view of a lockingvand turning Aspur 'for a carry-over train.

Figs. to :17 are views ott locking and turning spurs `for the various carry-over trains.

Numeral keys 1 of the typewriter depress levers 2 to vibrate bell cranks 3, to swing type bars Lt up to print against a platen 5, which is Vmounted on a carriage 6. The latter is driven by a spring-barrel 7, and has a rack 8 meshing with a pinion 9, connected to escapement Wheel 10, which is lll@ ies

controlled by dogs 11; said dogs operated by a universal bar 12, which is driven by heels 13 on the type bars.

Said keys 1 have stems 14 to depress arms 15 on rock shafts 16, forming parts of linkages 17, which are depressed by said keys to engage and depress computation pins 18, the latter suitably mounted ion bars 19. These bars 19 are elevated through the instrumentality of a dog 2O on the carriage 6, said dog engaging jacks 21 one after another, to depress the links 22 and vibrate levers 23, which engage linkages 24, to raise the rear ends of said bars 19 scrz'att'm.

After the keys 1 have been depressed to print the desired number on the work sheet, the typist pulls forwardly a handle 25, which is provided upon a rock shaft 26, the latter extending across the machine, and having at Aits ends segments 27, which mesh with idle pinions 28, meshing with opposite racks 29, which form parts of the general operator; said racks Iconnected by icross liars 39, 31.

The forward movement of said handle 25 carries the general operator forward, and cross-har engages such pins 18 as have been depressed by the keys, and drives forward the bars 19 accordingly; said bars having on their forward ends racks 32 to mesh with pinions 33, which are connected to dial or computing wheels, 3st; the latter loosely mounted on an arbor 35.

Each dial wheel is provided with a tooth 3G, which once in every revolution engages one of the teeth of pinion 37 to start the tens-carrying train, of which said pinion forms a part. rlhis is done while the dial wheel 3i is moving from 9 to 0; said tooth 36 turning said pinion substantially one ninth of a revolution. Said pinion is held in position by a light spring detent 37a.

Fast to said pinion 37 is a three toothed pinion 38 to mesh with a gear 39, fast on the dia-l wheel 34C next higher in denomina.- tion. Each tens-carrying train has its pinion turned one-third of a revolution at each operation thereof. The operation of a tenscarrying pinion and its train, after it has been started by the tooth 36 during the forward stroke of the general operator 29. is completed during the return stroke of said general operator by one of a set of spurs or segments of gears 40 fixed upon a shaft 4:1. In Figs. 3,4, 5, 6 and 9, the spur shown is the one for the fourth computing wheel counting from the right;-viz., the thousands wheel.

Said shaft l1 is driven from the rack 29 through an idle pinion l12 Fig. 3) and a pinion 13 meshing therewith and riding upon said shaft l1. Pinion 43 has a clutch connection to said shaft so as to revolve idly during the forward stroke of the general operator but makes one single complete revolution during the return stroke thereof. Said clutch comprises a ball il (Fig. 7) fitted in a pocket 4:5 in saidshaft and pressed by a spring G into a recess .117 in said pinion, the ball connecting the pinion and shaft during the return stroke of the pinion but .releasing the shaft during the initial stroke of the pinion.

The spurs et() are placed in helical order along` the shaft 41 so as to operate the tenscarrying trains ser/Swim, starting with the lowest denomination and proceeding to the highest. lllhen any tens-carrying train is in. its normal position, Fig. 3, it is inoperable by its spur li), since the pinion 37 is mutilated; every third tooth being cut away at L18 to make a clearance for the spur ll-O. #lo long as the tens-carrying train remains in normal p r sitien, the shaft l1 may revolve idly with respect thereto; but `when a train is uioved hy its associated tooth from the Fig. 3 position to the Fig. 1i position, one of the teeth i9 of the pinion moves into the path of its spur l0, and the latter, there-` fore, at the ensuing movement of the shaft 21, drives the tens-carrying train and advances the next higher dial wheel 3&1-, as shown in Fig. 5, until the normal position of F ig. 3 is reached. The shaft Zl1 and all the spurs then complete their revolution of normal position.

ln order to prevent overthrow of the tenscarrying train when it is started by the tooth 36 on any dial or computing wheel, there is provided fast to shaft 111 a series of stop teeth or lingers 50, one for each carry-over train. Each of these fingers normally lies in the path of the teeth L i9 on the associated pinion and is so placed that when this pinion is rotated by the tooth on the corresponding dial wheel it may turn under this impetus until the next higher tooth ii9 strikes said linger but no farther.

Thus on the forward stroke of the general operator the carry-over trains a re set, and on the return stroke the rotation of shaft -ll rotates the pinion i8 until, as shown in Fig. (i, a concentric portion 51 formed as a extension on the spur l0 temporarily locks the pinion against further ri'itation, and then continues its rotation until linger 5() is in position to intercept the teeth 119 ou pinion a8. lt will be seen that each segment or spur fir-0 with its extension .31 in addition to assisting the tens-carrying forms a fragnientary or temporary Geneva lock which prevents overthrow of the associated pinion 3'? and positively positions one of the gaps formed between every two pairs of the teeth 49, so that the segment or spur l0 will he free to rotate idly, subsequently, unless thev pinion 37 has been again advanced by its associated dial or computing wheel 3i.

At the conclusion of the forward stroke of the general operator, the dial wheels 3l are positively arrested against overthrow by -ineans of stops or locks 53, shown in the form of levers, which enter between teeth of the gear 39 on each dial wheel. These stops :33 are normally held in inoperative position by means of springs 54:, and are moved to locking position by means of a cam (Si), fast on the general operator, which raises a linger (il of a lever carrying at its other end a bail 58. This bail over-lies arms 57 on said levers 53, and so swings the locking toes of all the levers against the dial wheels when the cam 62 rides under the finger 61, which occurs at the end of the forward stroke of the general operator.

rlhese stops 53 are also en'iployed to lock the computing wheels against overthrow by the carry-over trains, and for this purpose a series of cams 65 is formed fast on the spur-carrying shaft lil, which cams each strike a linger 64 on an extension 5G on each stop 53 and swing each stop against its dial wheel immediately after its carry-over train has .been operated by its spur 40. Since tin-ire is no carry-over train operating the units wheel, the cam 65 may be omitted for said wheel.

'll e arrangement of carry-over actions including' cams G5, spurs Ll0, and stop fingers for the computing wheels, is shown in Figs. 10 to 17 Fig. l() being the one from units to tens wheel, F ig. 11 from tens to hundreds, etc.

Each stop or detent 53 prevents overthrow of its associated dial wheel when operated by a carry-over train.

The operation may be summed up as follows:

After numeral keys l have been depressed and pins 18 have been set, handle 25 is swung to move the general operator forward, and the bar 30 of said general operator picks up the computation racks vor bars as it successively strikes the pins in their different positions on the various racks, and thereby rotates the computing wheels 34. As the general operator concludes its forward stroke, its cam member 62 raises the lever against the tension of spring 66, and by means of bail 58 forces each stop or detent 5o to engage its respective computingl wheel and prevents overthrow thereof.

On the return stroke, the shaft 41 is rotated by the general operator. The springs pull the stops 53 out of the dial wheels, and any carry-over trains which may have been set are turned by their spurs 40. Immediately after each spur has passed the point at which it operates, the stop, check or detent 53 for the associated computing wheel is swung by its cam 65 to lock said wheel until `the whole surface of said cam passes the end 64: of said stop.

It will be noted that the racks onthe reciprocating pin frames are always in mesh with the wheels 35 and the con'iputing wheels 39, and in order that the computing wheels may always be driven in one direction, a one way clutch (37 having ten points of seizing is inserted between the wheel 33 and the computing wheel 3l. Usually a detent, such as 52, has been depended upon not only to prevent backward turning of the computing` wheels, but also for the purpose of preventing overthrow of the computing wheels when turned by the actuating devices. This invention belongsy to a class in which a. separate detent, such as 53, is employed, which prevents overthrow of the wheels when moved by the actuating devices, and it becomes no longer necessary to have the spring detent 52 of suliicient strength to prevent overthrow, but the spring thereof may be made comparatively weak, its function being, with the present construction, merely to prevent backward turning of the computing wheels, thus making the operation of the parts easier and less noisy.

Variations .may be resorted to within the scope of the invention, and portions of the improvements may be used without others.

Having thus described my invention, 1 claim:

1. In a computing machine, the lcombination with computing wheels, of means for rotating them, a lock for each wheel normally disengaged therefrom but positively moving to lock its wheel at the end movement of the means for rotating them, a carry-over train for operating each wheel from the one below, and means for moving each lock on movement of each carry-over train to lock each computing wheel immediately each carry-over train has completed the movement of its computing wheel.

2. In a computing machine, the combination with computing wheels, of means for rotating them, a lock for each wheel normally idle but positively locking its vwheel at the end movement of the means for rotating them, a carry-over train for operating each wheel from the one below, a tooth on each computing wheel for setting its carry-over train, positive-ineans for moving said tra-in when set, and a lock for arresting said V:arry-over train when it has been thus positively turned, said first-mentioned lock also locking each computing wheel when it is turned by the carry-over train driving it.

3. in a computing machine, the combination with computing wheels, of a carry-over train for turning each wheel by the one below, a tooth on each wheel for giving each carry-over train an initial turn. a stop limiting said turn, a spur for positively moving said train to vturn the computing wheel it operates, a lock to. arrest said train when, it

is moved by said spur, and a lock for said.

computing wheel for arresting it as it is moved bythe carry-over tram.

la In a computing machine, the comliination with computing wheels, of a carry-over train for turning each wheel by the wheel below, but normally out of mesh with each, a gear for positively turning each carryover train, a tooth on each computing wheel ttor turning its carry-over t ain so that the gear for positively turning it will mesh with it, a stop arresting said train in said meshing position, and a lock for arresting each computing wheel as it is turned by its carry-over wheel.

5. ln a computing machine, the combina-- tion with a gang oitl computing wheels and a gang of carry-over trains associated therewith, ot a gear for positively driving each carry-over train to turn the computing wheel it (hives, a tooth on each computing wheel :tot setting its carry-over train so that said train will mesh with its driving gear, a. stop on said gear for arresting said train in meshing position, and a lock on said gear for arresting` said train when it is turned.

G. in a computingl machine, the combination with. a gang of computing wheels and a gang oit carry-over trains associated therewith, oit a gear for positively driving each carry-over train to turn the computing wheel it'drives, a tooth on each computing wheel for setting its earry-oif'er train so that said train will mesh with its driving gear, a tooth on said -gear for arresting said train in meshing position, a loch on said gear for arresting` said train when it is turned, and a lock tor each computing wheel arresting it when said positive driving gear turns.

7. In a computing machine, the combination with a gane` oi" computing wheels and a gang et carry-over trains associated therewith, oit a shaft, a gear on said shaft tor positively driving each carry-over train to turn the computing wheel it drives, a tooth `on each computing wheel iter setting its carry-over train so that said train will mesh with its driving gear, a tooth on said shaft for arresting said train in meshing position, a lock for arresting` each computing wheel, and a cam on said shaft :tor operating said lock when said driving gear has turned.

S. A computing machine having computing devices, operating devices therefor, and carrying mechanism which preliminarily set and subsequently operated to carry; and comprising in combination, an overthrowstop-piece acting to prevent overthrow of the carrying mechanism during the preliminary setting thereof and also at the carrying operation.

9. ln a computing machine, the combination with settable members, of computing wheels, a reciprocating operator to carry into said wheels numerals represented by the members set, means for locking said computino` wheels at the end et one stroke l E u of said operator, carry-over trains arranged to be set to turn one computing wheel by the one below, a tooth on each computing wheel to set the carry-over train for the adjoining wheel, a spur for turning each carry over train positively moved by the opposite stroke or said operator, and a tooth locking said carry-over train against overthrow, moved to inoperative position while said carry-over train is moved.

10. in a computing machine, the combination with computing wheels and mechanism for turning them, of a carry-over train including gear teeth for each wheel, a positively driven shaft for successively operating said trains by their teeth, a lock on said shaft for each train to prevent its overthrow, and means on said shaft lor-,hin each computing wheel when it is turned by its train.

1l. ln a computing` machine, the combination with numeral wheels, of a loch tor each numeral wheel and normally disengaged therefrom for preventing overthrow thereof, means for carrying numbers into said numeral wheels operating all ol said locks simultaneously, and carry-over mechanism operating said locks successively.

l2. The combination with a series oi computing wheels, oi1 a series et locks normally in inoperative position, one individual to each of said computing wheels, shitting means universal to all said locks arranged to move the same from inoperative to operative position eoncomitantly, and shii'ting means individual te each ot said locks for moving the same from inoperative to operative position as individuals.

13. The combination with a computing wheel, o1PA a reciprocating lock for said wheel normally disengaged therefrom, means separate from said lock for swinging said lock to eil'ective engagement with said computing wheel solely for an instant corresponding to the termination oi the movement et the associated computing wheel so as to arrest the computing wheel to prevent overthrow, and means for moving said loci; after actuation to ineffective normal position.

la. The combination with a series of coinputing wheels normally disengaged therefrom, of a series et reciprocating locks :tor said computing wheels, driving means separate from said locks for concomitantly rotating aid computing wheels variable amounts, and shitting means for momentarily rendering said locks effective and then moving said locks to ineiiective normal position relieving said computing wheels of the drag oi said locks.

l5. The combination with a computing wheel, et a lock for said computing wheel, a carry-over mechanism for said computing wheel, means for running up a number on said computing wheel, and actuating means for said lock operating to momentarily shift said lock to its effective position at the termination of a movement of said computing wheel and then moving said lock to an ineffective position, said actuating means being operable either from said carry-over mechanism or from said running-up means according to whether the movement of said computing wheel .which it is desired to arrest was caused by the .former or the latter.

16. rl`he combination with a plurality of computingwheels, of a carry-over train for each computing wheel, means for setting the carryover train of each computing wheel from its associated computing wheel, an overthrow-preventing lock for said carryover train, .a lock determining the inactive position of the carry-over train, and a temporary lock for arresting' each lcomputing wheel after an actuation by the associated carry-over train.

17 An assisting tens-carrying member having an arm with a gap therein forming a spur on one side and alocking extension on the other side, said locking extension being located to the rear with respect to the direction of movement of said spin', a camdiaving a definite relative position with respect to said spur, and a stop finger having a definite relative position with respect .to said spur and said cam.

18. The combination with an assisting shaft, of a series of spurs spirally located on said shaft, a series of cams spirally located on said shaft and having a definite relative position with respect to saidspurs, and a series of stop fingers, one for each of said cams and said spurs, located in alinement with each other. f

19. A computing machine having computing devices, including dial wheels, operating devices therefor, and carrying mechanism which is preliminarily set and subsequently operated to carry; and comprising in combination, a member for preventing overthrow of the carrying mechanism during the preliminary setting thereof, and means controlled by said member on movement thereof preventing overthrow of the dial wheels during carrying.

20. The combination with a series of com` puting wheels, .of actuating mechanism for said computing wheels, a delayed carry-over mechanism for said computing wheels, a single set of overthrow locks normally disengaged from said wheels, and means for moving said locks into engagement with `said computing wheels at the termination of any movement thereof either by said actuating mechanism, or by said carry-over mech anism to prevent overthrow of said computing wheels.

21. The combination with a series of com? puting wheels, of. a series, of overthrow locks, one for each of said computing wheels, actuating mechanism for said computing wheels, tens-carrying mechanism for said computing wheels, a general operator for driring said actuating mechanism on its initial stroke, and driving said tens-carrying mechanism on its secondary stroke, shifting means for bringing said overthrow locks into play at the end ofthe initial stroke of said general operator and acting to disengage said overthrow locks at the beginning of the ksecondary stroke of said general operator, and means for bringing said ylocks into play individually during' the secondary stroke of said general opera* tor and subsequent to the carry-over action for veach computing wheel, so as to prevent overthrow of said cinnputing wheels by said tens-carrying mechanism.

The combination with a series of coniputing wheels, of tens-carryiiig mechanism for said computing wheels, acting successively from each lower to each higher denomination from lowest to highest, overthrow locks normally disengaged from said wheels, one for each thereof, and operating means for said locks cominginto play successively from lowest to highest, so as to move said locks to engage said wheels just subsequent to each possible carryover operation ofsaid tensecarrying mechanism.

23. The combination with a series of computing wheels, of actuating mechanism for running up numbers in said computing wheels, carry-,over mechanism for carrying between said' computing wheels, and a siiigle set of overthrow locks' normally disengaged from said wheels, said locks being controlled by said actuating mechanism and said carry-over mechanism, so as to be moved by either into operative engagement with said wheels, Vin order to prevent overthrow of said computing wheels by either said actuating mechanism in running up numbers, or by said carry-over mechanism in carrying from one computing wheel to another.

24. A computing machine having computing devices, operating devices therefor, carrying mechanism which is preliininarily set and subsequently operated to carry, and a general operator for the computing devices; and comprising in combination, means acted on by the movement of said general operator for preventing overthrow of the con'iputing devices during computation, a member for preventing overthrow of the carrying mechanism during the preliminary setting thereof, and means called into action on movement of said member and acting on said overthrow preventing means for preventing' overthrow of lthe computing devices at the carrying operation.

25. The combination with a series of computing .,wlieels, of driving mechanism for ruiming up numbers on said computing wheels, and overthrow locking mechanism momentarily engaged by said driving mechanism and engaging said computing wheels to prevent overthrow of said computing wheels by said driving mechanism, and instantly disengaging from both said computing wheels and said driving mechanism to render said computing wheels free for sub? sequent action, and itself free for subsequent action.

26. A carry-over mechanism comprising a series of driving spurs, a series of stop lingers having a definite relative position with respect to said driving spurs, and a series of cams, one for each spur, having a definite relative position with respect to said driving spurs.

9.7. A con'iputing machine having com p uting devices, operating devices therefor, and carrying mechanism which is preliminar-ily set and subsequently operated to carry; and comprising in combination, an overthrowstop-piece which in normal position actsl to prevent overthrow of the carrying mechanism during the preliminary setting thereof, and when moved acts to prevent overthrow at the carrying operation.

Q8. A computing machine having computing devices, operating devices therefor, and carrying mechanism which is preliminarily set and subsequently operated to carry; and comprising in combination, a single stoppiece, said piece being provided with means for preventing overthrow of, the carrying mechanism during the preliminary setting thereof, means for operating the carrying mechanism when set, and means for preventing overthrow of the carrying mechanism at the carrying operation.

.29. A computing machine having computing devices, operating devices therefor, and carrying mechanism which is preliminarily set and subsequently operated to carry; and comprising in combination, a control device operating as a single piece, said device controlling the carrying mechanism during the preliminary setting thereof to prevent overthrow, the operation of the carrying mechanism wnen set, the overthrow of the carrying mechanism at the carrying operation, and the overthrow of the computing devices at the carrying operation.

30. A computing machine having com-` puting devices, operating devices therefor, and carrying mechanism which is preliminarily set and subsequently operated to carry; and comprising in combination, a rotatable tappet piece, and means under control of said piece during a single rotation thereof for preventing overthrow of the carrying mechanism during the preliminary setting thereof, the operation of the carrying mechanism when set, the overthrow of the carrying mechanism at the carrying operation, and the overthrow of the computing devices at the carryii'ig operation.

31. In a computing machine, the combination of a gang of computing wheels and a gang of carry-over trains associated therewith, a shaft, a gear on said shaft for posi.- tively driving each carry-over train to turn the con'iputing wheel it drives, a tooth on each computing wheel for setting its carry-over train, so that said train will mesh with its driving gear, and a tooth on said shaft for preventing overthrow of said train when moved by said tooth on. said computing wheel.

32. In a computing machine, the combination with computing wheels, of a general operator to carry numbers into said computing wheels, carry-over trains arranged to be set to turn one computing wheel by the one below, means on each computing wheel. to set the carry-over train for thc adjoining wheel, means for turning each carry-over train on movement of the general operator, and a rotatable tooth locking each carry-over train against overthrow during the setting thereof by the computing wheels.

ln a computing machine, the combination with computing wheels, of a reciprocating operator to carry numbers into said computing wheels, means for locking said wheels at the end of one stroke of said operator, carry-over trains arranged to be set to turn one computing wheel by the one below, a tooth on each computing wheel to set the carry-over train for the adjoining wheel, a spur for turning each carry-over train moved by the opposite stroke of the reciprocating' operator, and a rotatable tooth locking said carry-over train against overthrow during the setting thereof by the computing wheels, said locking tooth being moved to an inoperative position by its rotation.

?ill. ln a computing machine, the combination with computing wheels, and carry-over trains having gear teeth for each wheel, of a shaft for successively operating said trains by their gear teeth, locking means on said shaft for each train to prevent its overthrow during preliminary settingI and during carrying, and means on said shaft acting` to prevent overthrow of cach computing wheel `when it is turned by its train.

JOHN N. 'lll-IORNION.

lilitnesses C. RIPLEY, C. NnwnLL.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. C. 

